Calculating-machine



E. C. WALTER.

CALCULATING MACHINE.

APPLICATION FILED MAR. 2|. 1917.

1,325,969. Patented Dec. 23,1919.

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Patented Dec. 23, 1919.

4 SHEETS-SHEET 2- E. C. WALTER. CALCULATING MACHINE. APPLICATION FILED MAR. 21, 1917.

Patented Dec. 23, 1919. I

4 SHEETS--SHEET 3- E. C. WALTER. CALCULATING MACHINE. APPLICATION FILED MAR. 2|. 1917.

1 ,325,969. Patented Dec. 23, 1919.

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m mnunulnunluu"an"'nnunnnluu n n/ "In", "nu In u: u! p NITED STATES PATENT OFFICE.

EDWARD WALTER, OF NEW YORK, N. Y., ASSIGNOR TO HARRY T. AMBROSE, OF

ORANGE, NEW JERSEY.

CALCULATING-MACHINE.

To all whom it may concern:

Be it known that I, EDWARD G. \IVALTER, a

citizen of the United States, residing at New will register zeros.

Bookkeeping, bank, and statement work often shows a condition which is termed a credit balance, overdraft, etc. and which condition will herein be termed the amount below zero. It is herein shown on the machine as the complement of the negative number. Therefore,if in making out a bank statement the account appears as overdrawn, the calculating machine (embodying, my invention) will register an amount which is the complement of the negative number, and the amount overdrawn would be the negative number or the amount sufiioient, by adding, to make the calculating machine register zero. It is, therefore, an object of the present invention to provide a structure for effecting this result.

The determination'of the negative num ber, which is the complement of the number showing, is accomplished by means actuated by the calculating machine when the same is operated by the zero-producer to produce zeros thereon, as will hereinafter be explained.

The device involving such means is normally out of operative connection or. engagement with the calculating machine, but is mounted on the same in such manner that it may quickly be positioned'into operative engagement therewith and be operated thereby. This arrangement relieves the calculating machine of the burden of operating the device e-Xcept when desirable and, thus, only while the same is in operative engagement therewith. I

The present embodiment of this device is shown as an attachment associated with an Specification of ietters iatent. Patented Dec, 23, 1919,

Application filed March 21, 1917. Serial No. 156,365.

adding and subtracting machine, such, for example, as that disclosed in my pending application, Serial No. 637.199. which became U. S. Patent No. 1,224 872 guanted May 1, 1917, and reference thereto ishere made for a more complete description thereof; but this device may obviously be used in connection with other types of calculating machines, and it may also be used as a separate and distinct device in connection with mechanism wherein the false amount (or the amount below zero) may be set up so that the figure-wheels of this device may show the true or complementa-l number of the false amount set up. V I

Means are provided in the machlne for resetting or returning the instrumentalities of the devlce to normal condltlon preparatory to further use; and means are likewlse provided for closing the sight-opening of the machine through which the numerals on the figure-Wheels are observed,'except when showing a negative number.

Other features, both mechanical and practical, will be apparent from the following description of my improved mechanical construction and of its mode of operation.

In the accompanying drawings, which exemplify a practical embodiment of-the' device:

Figure 1 is a view in side elevation of my calculating machine provided with a complement-determining device constructed in accordance with my invention, and showing the connections between the twostructures;

2 is a view partly in sideelevation (similar to Fig.1) and partly inflvertioal section to show the interior of the complement-determining device and the key-connections;

Fig. 3 is a fragmentary view in elevation,

of a part of the, structure and shows, the" first carry-plate thereof in raised position and the aperture (in the complcment-determining device through which the figure-'1 wheels are observed) opened;

Fig: 4 is a fragmentary view in perspective of locks for carry-plates, of the connections between the first look and the zero-producer mechanism of the calculating machine for unlocking the same, and of a latch for holding the complement-device in operative relation with respect to the calculating ma- I chine;

i the of which the main-gears of the complementdevice are composed; I Y

F 8 is a view in perspective of one of gure-Wheels; r Fig. 9 is a fragmentary view in elevation of the'casing and exposed peripheries of the figure-wheels; and Figs. 10 and 11 are views in plan and in vertical section of a modified form of machine. v

The calculating machine, described in my aforementioned application, is adapted to produce additive and subtractive computations. These computations are produced by normally rotating figure-wheels in one, direction when adding and in the opposite direction when subtracting. Now, if these figurewheels are rotated a distance greater than normal in a subtractive direction, the result would be an amount below zero, and this would be distinguishable from a result above zero by the fact that there would be nines showing on the series of figurewheels to the left of that amount which I will call the false number because the amount below zero has been subtracted from the amount (constituting the computing caacity of the machine) plus one; as the folowing shows: Assuming that the calculating machine contains eight denominational places and figure-wheels and that each is standing atzero; now, if the machine is operated to subtract 3 7 5., the figure-wheels of the machine will show an amount which is below zero; for example:

O00 000 O0 3 amount subtracted.

999 996 25= false number.

The negative amount or complement of cause all the Wheels to be turned to zeroposition to show zeros; as

999 996 2 5 =-false number.

3 74 999 999 99]=3 75= complement.

15000 000 00 p NOW, supposing (for example) that the calculating machine, after a diflerent compu'tation, show. 000'005 34 and that the amount of 6 8 is then'subtracted therefrom, the machine would show 6 83=amount subtracted. v 999 998 51 =false number. Thecoiuplement of this number would be that amount which will cause the figure- 1 wheels' to rotate m an additive direction un til each shows 9, with the further adding of 1 to the unit-column. This action would cause all the carrying mechanisms of the machine to operate and turn all the wheels to zero-position; as

999 998 51 false number.

I 48 Y 999 999 99]=1 49= complement.

' amount necessary to raise the same all to nines, which constitutes the capacity of the calculating machine), will appear thereon. As one additional unit is necessary, however, to raise this amount to clear the register so that it will only show zeros, means are provided for automatically causing the first figure-wheel of the complementdevice to move one additional space, in an additive direction, each time the device is operated by the zero producer of the calculating machine, and carrying mechanism is also provided for the device to efi'ect a carrying of the tens-units from one figure-wheel to another.

The mechanical construction of my preferred embodiment (as here shown) is simple, it is easy of action, and it is certain in operation, all as willnow be explained.

In 1 to 9, I-have illustrated the structure as operable in conjunction with a carriage C which travels in relation to a calculator or register R. The carriage includes numeral-keys 1. These keys, when operated, transm t motion to and actuate select- 5 ing-devices 2 in the register R, and these,

in turn, when operated by the pull-handle H, will (through interposed mechanism) cause rotation of gears 3 in an additive or subtractive direction, according to the position of a setting-lever 4 which controls the direction of rotation of the parts, The gears 3, which are in mesh with figurewheels 5, will cause the same to rotate (clockwise or counter-clockwise, as the case may be) and display, through a sight-opening 6 in the register, the result of thecomputation.

The gears 3 are loosely mounted on a shaft Land on thisis a ries of arms 8, one of which has a normal tendency to swing the pawl on its fulcrum.

Fastened on the shaft 7 is a zero-producing lever 11- which, when held in its lowermost position (as shown in Fig. 2) causes all of the awls 9 to compress their re spective springs 10 and engage the pawls with stops 12. When, however, the lever 11 is moved for the purpose of producing zeros in the calculating machine or register, the pawls 9 will be moved away from the stops 12 and the springs 10 will cause .the pawls 9 to swing on their respective .fulcra.

The gears 3 have fastened to their sides, at the right, a ring 13 provided with a ries of three internal teeth 13 against which the pawls 9 abut and cause rotative action I of the gears 3 and of each figure-wheel 5 jection 20* (Fig.

in a subtractive direction until all of the figure-wheels are registering zeros. It is to b understood that a wheel which is registering nine will be rotated nine unitspaces, while a wheel which is registering two would be rotated only two unitspaces; and so on throughout the group of wheels.

The calculating machine includes side- Qalates '14 and these are provided with up- .standing lugs 1-1 (Fig. 2), and these constitute a support for my improved complement-device, which includes a casing A, new to be described. This comprises side-plates a. The device is fulcrumed'on these lugs by a shaft 15 journaled in the side-plates u and normally held in a raised position by two-membered springs 16, one of which appears in Fig. 2, and which are secured to the side-plates 14;.

Loosely mounted on a shaft 17 supported in the side-plates a is a gear 18 which is rovided' on its right-hand side with a ratchet 19 (shown detached in Fig. 7 and in Figs. 2 and 3 partly in dotted lines) and, on the left-hand side with a disk 20 (Figs. 2 and 3) formed with a tens-carrying pro- Meshing with each gear 18 is a figure-wheel 21 corresponding to the figure-wheel 5 in the registerl The denominational numerals or figures are. im-

' nine normally appears printed on the periphery of each wheel, as shown in Figs. 8 and 9, and the-numeral through a sightopening 22in this device.

' The device. A is equipped with a button 23 upon whichthe operator presses when it is desired to position the complement-device into operative engagement with the calculating machine. When so depressed, the gears 18 of thecomplement-device mesh with thegears '3 of the register and are fourth, fifth, etc.,

held in mesh therewith by a spring-pr med;zero-producer tive engagement with the calculating machine.

that should the calculating machine be showing a false number and it be desired todetermine what is the negative or complementnumber thereof, this can be accomplished by positioning the complement-device (in the manner already explained) into operatiVeengagement with the calculating machine and then by returning the figurewheels 5 thereof to zero by effecting action of the lever 11, arms 8, and pawls 9 so that the gears 3 may severally be rotated distances equal in unit-spaces to the amount showing on the respective figure-wheels of the calculating machine. The gears 18 of the complement-device, being in mesh with the gears 3, will be rotated a corresponding extent and, thus, the figure-wheels 21 of the. complement-device will. be correspondingly rotated in a subtractive direction and, as these figure-wheels normally stand at From th foregoing, it will be apparent I nines, they will then show the negative number which is the complement of th number that was appearing on the figure wheels 5 in the calculating machine. In other words, there will be shown on each figure-wheel of the complement-device the difference between nine and the number that was showing on the corresponding figure-wheel 5 of the calculating machine: If the calculating machine contains, for example, eight denominational places or figure-wheels and they are showing 999 999 25. and if, then. the complement-device is placed into operative connection therewith and the zero-producer lever 11 of the calculating machine is operated to return its figurewheels 5 to zero, the first-wheel at the right would move five unit-spaces and, at

the same ti1ne,the first unit-wheel 21 of the complement-device would (as it normally stands at nine) be moved five unit-spaces in a subtractive direction. This will cause 1 to be presented to view, and the second figure-wheel will also be moved two unitspaces which, deducted from nine, would cause the 7 to appear; and then the third,'

wheels would be moved nin unit-spaces. This would cause all the corresponding wheels of the complementdevice to be rotated from f9? to 0. Thus, at the completion of the movement of the lever 11, in this particular lit) example, the complement-device would show the amount of 000 000 74, or the difference in amount between the false figure showing on the calculating machine and the capacity thereof, which is 999 999 99.

To obtain the negative or trm complement number in any instance, the first wheel (at the right) of the complement-device must then be rotated one additional unit-space in an additive direction, after the false number has been subtracted from all nines of the complement-device, and this is accomplished bythe following mechanism: Adjacent the right-hand side of each ratchet 19 is a carrying plate 27 fulcrumed. on a shaft 28 j-ournaled in the casing of the device. Attached to each of these plates is a spring 29 of suflicient strength to raise the plates and effect a turning of the connected parts. The forward end of each of the plates is provided with two projections 27 and 27". The upper projection 27 extends toward the right (as viewed in Fig. 3) andis adapted to enter a recess 30 in a lever 30 (supported on a shaft 30*) and hold the plate in a lowered position against the act-ion of the spring 29. The lower projection, 27*, on each plate extends to the left and is adapted to engage with the teetlrof the ratchet 19 to move the same when the plate is released from the recess or notch 30 in lever 30. The first lever 30 at the right (as viewed in Fig. 4)

has connected to Its upper end a link 31 attached to the upper end of an arm 32 which, in turn, is fulcrumed on a stud in the casing. The lower end of the arm 32 lies in the path of movement of a projection 34 on a disk 34 keyed on the shaft 7 and rotatable With the same when the zero-producer lever 11 is operated. A light spring 35 attached to the ing will cause the lever to abut normally against the upper projection 27 The lower end of the latch 24 also lies in the path of movement of the projection 34* on the disk 34 and is adapted to be moved by the same. Therefore, assuming, as in the last example given, that the lever 11 has been operated to produce zeros in the calculating machine and that this action has produced the complement of the false number, to the extent of the capacity of the machine, then the projection 34*, having ap proached and engaged the lower ends of the latch 24 and the arm 32, will move the same to such an extent that just as soon as the zero-producer has completed its operation it willl cause the hook 24 of the latch to release the complement device and the spring 16 will raise the same. Simultaneously, the arm 32 will have been moved to such an extent that the notch 27 will release the plate 27 and the spring 29 will then raise the same.

While the plate 27 is rising, the projection lever 30 and to the cas- 27 will engage one of the teeth of the ratchet 19 and rotate the latter one unit-space in a direction opposite to that in which it was moving when rotated by the zero-producer of the calculating machine. The projection 27, when in engagement with a tooth of the ratchet 19, will hold the same from overthrowing.

The tens-carrying projections 20 on the disks 20 are positioned adjacent cammed portions 30 of the levers 30 when the figurewheels of their denominational section are standing at nine. Should, however, any of these projections pass under its respective lever 30, the plate'27 (being held by the notch thereof) will be released therefrom and the spring 29 attached thereto will cause it to rise-so that its lower projection will engage a tooth of the gear to the left of the one under operation and cause rotation thereof and of its figure-wheel to the left one unit-space. Now, should the adding of this unit-space to the wheel to the left cause the release of the plate for that denominational position, then, the next gear and wheel to the left will also be moved one unit-space; and this action of carrying the tens units will be successive from one denominational position to another.

The rear ortions of the plates 27 are provided witi rollers 36 which will, when the plates are released from the notches, be moved into the path of movement of a cam 37. This cam 37, when revolved, will. return the plates to normal position and the notches 30"" will again hold them until released. Light coil springs 38 are adapted to hold the arms 30 (for the plates of all denominational positions except the unit position) against the projections 27.

' Fnlcrumed on a figure-wheel supporting shaft 39 is a shield 40 which has an angulated port-ion lO extending across all the figure-wheels and normally is directly back of'the si ht-opening 22 to cover the figures Another portion of 'on the figure-wheel's.

with a slot 40 in the shield is provided which operates a pin 27 on the first plate 27 to cause movement of the shield each time that the first plate 27 rises, and action occurs every time the device is being, operated. The downward movement of the shield 40 opens the sightopening and exhibits to view the numerals of the negative number. When the first plate is returned to normal position, the sight-opening is again closed.

Means are also provided for returning the actuated parts to normal positio'n after each operation of the device and preparatory to another operation thereof: In the first place. lit'is'to be noted thatthe first movement of the pull-handle H. after an operation of the device for determining a negative number, will return the parts to normal posit-ion in the following manner The handle (through a segment 41, gear 41 and disk 41) operates a pawl 42 and a ratchet 43 and causes a gear 44 to rotate one-quarter of a turn on each operation thereof. Meshing with gear 44 is an intermediate gear ,45 which, in turn, meshes with a gear 46 fast on the 'end of the shaft. 15. The gears are so dimensioned that operation of the pull-handle will cause complete rotation of theshaft 15. i

- It is to'be understood that the shaft15 carries a cam 37 for each plate 27, and alsoa mutilated gear 47 for every denominational position contained in the device. Meshing with the gears 18 and adapted to '-are mutilated gears to the mutilated sections thereof, that the gears 48 may be rotated without colliding with gears'47. Rotation of the shaft 15 will cause the cams37 to return the plates 27 to normal position and cause the toothed .sections of the gears 47 and 48*tomesh and return the gears 48 and, consequently, the fig' ure-wheels to normal position.

If any of the figure-wheels shall have been rotated in an additive direction from 9 ,to

0, the projection 27 on the plate 27 for that figure-wheel will (when being returned by the cam 37) abut' against the rojection 19 on the plate 19 and return t e figurewheel in a subtractive direction to normal position orthat position wherein the numeral 9 is directly back of the sight.opening 22. i i

In lieu of the described connection be tween the handle H and the shaft 15 for resetting the device to normal position, a lever '49 (Fig. 1) may be secured to the outer-end of the shaft 15 so that a complete revolution of the same will operate the related parts and'accomplish the same functions thereof I as when actuated by the handle-H.

a or negative Having explaine'dthe operation of the various partsof the structure, the adaptability of the device tocomme'rcial purposes will now be briefly statedq n Having completed a computation on the calculating machine, if the resultthereof is below'zero and it be desired to ascertain the. negative number, the complement of the false numberregistered thereby, the operator by the'button '23, moves the device into operative relation to the calculating achine and then operates the zero-producer liiver 11 of the latter. This action transforms the false number, or .the complement of the negative number, into the true then" appear through the sight-opening of the riomplement-deVice-and releases the de vice from operative engagement with the calculating machine. Subsequent operation of the pullhandle of the calculating machine resets the complement-device and prenumber-which number will &

,the invention to make, the same applicable to other designs of machines: For instance,

Figs, 10 and 11 illustrate an embodiment wherein operating keys or slides 50 are housed Within a casing 51, a casing 52 of the complement-device 53 being positionable in relation thereto, as in the structure already described: Normal1y,all of'the slides 50 stand at zero-position: The operator: presses the casing 52 downward to engage a gear 54 corresponding to the afore-mentioned gear 18 in the principal embodiment with a pinion 55 which is operated by the rack on the slide '50.- The gear 54 meshes with a number-wheel '56. Each of the slides 50 normally stands at Zero-position, as stated, and thetwheel 56 will show 9 When the operator actuates one or I more of the slides to bring the selected numher into position, the complement of this number will be made to show on the number- Wheels. If, then, an unlocking lever 57 is operated to actuate a latch 58,-similar to the latch 24-this action will add the additional unit necessary to make the correct amount and effect a release of the gear 54 e from engagement with the pinion 55, Simi larly as in the first structure described.

The invention, as herein disclosed, in-

to both the structure and method I herein make claim.

WhatI claim-is'z' y a I 1. In -combination, an adding-and-subtracting machine and a complement-determining device, the machine and device each including a-set' of figure-wheels, one set being adapted to be operated independently Y of the'operation of the other set; the figurewheels of the device normally standing at nines until brought into connection with and operated by the figure-wheels of the machine to produce the complement of a number o n 'the wheels of the device when said number is subtracted from the wheels either-machine, and means for automatt pendently of action of the other set, ,zero

volves the structure described and, also, the method practised in connection therein; and

producing mechanism ,for the machine for rotating its wheels in a subtraetlve direction toward the1r zero-posltion, means for retating the wheels of thedevice in a subtracp l'ng them elther simultaneously or independ- 70 a v to 5 tive direction when the zero-producing mechanism is operated, and means operable by the zero-producing mechanism to reverse the direction of rotation of the wheels ofthe device to complete the complementdetermining operation. 4

3. In combination, keys for setting up a number, a complement-determining device associated therewith and including figurewheels operable thereby to rotate the wheels I of the device in a subtractive direction for producing, within. one unit, the complement of thenumber set up on the keys and including also a unit figure-wheel, and an instrumentality operable to disconnect the keys and figure-wheels and for reversing ro-\ tation of the. unit figure-wheel to produce the actual, required complement.

4. In combination, a calculating machine including zeroproducing mechanism for eliminatlng numbers set up in the machine, I a com-plement-determlnlng devlce as'soclated with the machine and actuatable by the zeroproducing mechanism to produce, within one unit, the complement of the number eliminated by the machine during the action of the zero-producing mechanism and in- I eluding a unit-wheel, and means releasable by the zero producing mechanism to rotate the unit-wheel of the.complement-determininc device one unit-space in a direction opposite'to that in which it is rotated by the zero-producing mechanism before being released therefrom to produce the required com plement-number.

4o 5. In combination, a calculating machine,

a complement-detennining device comprising a unit-wheel, the machine and device each including a series of figureovheels and each series being independently rotatable,

5 the wheels of the calculating machine producing the result of additive and subtractive computations while the wheels ofthe device remain stationary, means for connecting the two series of Wheels, means for effecting rotation of the unit-wheel of the device, means for rotating the connected wheels in 'asubtractive direction until a zero-position. is produced on the wheels of the machine and, then,disconnecting the series of wheels and releasing the unit-wheel rotating means for causing IOtEUtiOII of the unit-wheel in an additive direction, and means for effecting rotation of all of the wheels of the device in an additive direction untilthe nines position 30 thereof is attained.

6. In combination, a calculating machine including a series of figure-wheels on .which a number may be set up, a complemmtld termining device including a serles' of fig- 35 ure-wheels and a unit-wheel, the; wheels of com lement of a number presenting to view the nines number i the machine being alternately rotatable in opposite directions independent of the act1on of thewheels of the devi means intersed between both series of w eels for movently and, when moved simultaneous disconnect the .wheels one from the other, and meansflreleasable thereby for ro tating the wheel'slof the" device independently of the wheels of the calculating machine; said operations causing the figurewheels of the device to exhibit to view the previouslyset "up in t e calculating machine.

.7; In combination, a calculating machine so including a series of figure-wheels, a complement-determining device-also includi a series of figure-wheels and a unit-Wheefi the figure-wheels of the machine being 0 erable in either direction'for. setting u t e 35 result of additive and subtractive c0 puts-Q tions independently oi the action 01th?) wheels of the device, means for connectin the two series of wheels for'simultaneou'; rotation, means for rotating both serieso wheels in a subtractive direction and for disconnecting the connected series, means for subsequently rotatingthe unit-wheel one unit-space in an additive direction, and

means for moving each wheel of the series i one unit-space in an additive direction. f

8. A structure includingtwoseries of figurewheels, each rotatable independently in two directions, one of the series normally v scribed thereon while the other series re; sents to view the result of additive and sub= tractive computations, means for connecting the two series for simultaneous rotation,.means for actuating the connecting means to rotate both series in a subtractive direction, said actuating means also disconnecting 'one series from the other, and means releasable by the disconnecting means forrotating one wheel of one series in an additive direction, means for effecting rotation of all of the wheels of the discpnnected series in an additive direction, and 5 independent means for effecting action of the Wheels of both series in an additive di- 1 15 rection.

9. A calculating machine including an actuating lever and zero-producing mechanism, incombination with a complement-determining device associated therewith and positionable into operative relation thereto, the machine and device each including a series of figure-wheels rotatable in a subtractive direction by operation .of the zeroproducing mechanism, means for connecting the wheels of the machine'and device,"mech- 'anism releasable by the action of the zeroseries of figure-wheels, means releasable by the action of the zero-producing mechanism for causin independent rotation of the wheels of t e device in an additive direction to complete the complement-determining operation, and means operable by the actuat-- tatable in one direction for producing additive computations and in the opposite d-irection for producing subtractive computations, said wheels displaying to view the complement of a negative number whenever they have been rotated adistance greater in a subtractive than in an additive direction, a complement-determining device connectible with the calculating machine and including a ,set of figure-Wheels normally discon;

nected from the figure-wheels of the calculating machine and remaining stationary when the wheels of the machine are producing the complement of a number and connectible thereafter with the wheels of the machine and rotatable simultaneously therewith, said complement-dctermining device also including a unit-wheel, zero-producing mechanism in the calculating machine and operable to rotate its figure-wheels in a subtractive direction toward zero-position and also to rotate the figure-wheels of the device in a subtractive direction an equal extent to c roduce, within one unit, the negative nunier, two arms carried by the device and shiftable by the zero-producing mechanism after such mechanism has rotated the figurewheels, a spring-actuated plate, and an arm for actuating the plate; one of the aforementioned two arms operating, when shift ed, to release the complement determining device from operative connection with the calculating machine, and the other connected to and operating the arm for releasing the springactuated plate, the latter operating to rotate the unit-wheel of the device one unit-space in an additive direction and I thereby producing the aforementioned negative number.

11. In combination, a calculating ma chine and a complcment-determining device fulcrumed on the calculating machine and normally out of operating connection therewith but movable into connection with the same, zero-producing mechanism for the calculating machine, a locking inst-rumentality for holding the device in operative connection with the calculating machine and, having one end disposed in the path of movement of the zero-producer and shiftable thereby for releasing the device and disconnectin the same from the machine, a douhie-ended arm fulcrumed on the device and having one end in the path of movement of the zero-producer and shittable thereby, a notched arm, a link for connecting the other end of the double-ended arm to the notched determining device fulcrumed on the calcuanm, a springactuated plate provided with a plurality of projections, a ratchet assomutilated gears in mesh with said gears and rotatable by the same, and a second series of mutilated gears lying substantially in the 0 same plane as the first series and normally out of mesh therewith but adapted when the second set is rotated to mesh with the other series and to be rotated to normal position by the second series.

13. In combination, in a calculating machine, a set of figure-wheels, a set of gears constantly in mesh therewith for rotating the same in either direction, a complementlating machine and including a series of gears adapted to be positioned in mesh with the gears of the machine, a series of figurewheels meshed with the series of gears in the device, each gear therefor having a ratchet provided with a projection, a spring-actuated plate provided with 'a projection adapted, when the, plate is shifted in one direction, to enter a tooth of the ratchet and, when shifted in the opposite direction, to abut against the projection on the ratchet.

l-l. The combination in a calculating machine including additive-producing instrumentalities, of a device tiltably attached thereto and tiltable in relation therewith, of ,55

calculating machine associated therewith and actuatable thereby to effect a selection in the machine and including wheels rotatable either in an additive or a subtractive direction, selecting means in the machine, operating means for causing the selecting means to effect a computation, meansdfor eliminating the result of the computations from the calculating machine, releasable means operativcly associated therewith, a complementdevice operatively associated with the calculating machine and receiving movement from the same for exhibiting the comple ing the-complement number from the complement-device.

16. In a device of the kind described including a figure-wheel and provided with an aperture through which the figures on the wheel may be observed, a shield for closing the aperture, a lever provided with a notch, a plate provided with a projection adapted to enter the notch and be held thereby in a lowered position, a spring connected to the plate for raising the same when released from the notch, and a connection between the shield and plate whereby the former will be moved away from the aperture whenever the plate is raised.-

17. A t; ewriter-operated computing machine including figuye-wheels, gears for rotating the wheels in opposite directions, ratchets attached to the gears, a lever, connections for engaging the teeth of the ratchet to turn the gears and figure-wheels in one direction, gears normally out of mesh with the wheel-rotating gears but engageable therewith for operation thereby when under control of the'lever and connections, figurewheels in operative connection with the normally disconnected gears, both sets'of figure- Wheels being rotatable in a subtractive direction when the lever and connections are operated, a disk attached to the lever, and a plurality of spring-pressed arms lying in the path of movement of the disk and movable thereby when the lever is operated.

18. The combination in a device of the kind described, of a chain of mechanism comprising'a figure-wheel, a gear for rotating the sam ein either direction, a mutilated gear in mesh with said gear for moving the same in one direction, a cam-actuated plate for moving the gear in the opposite direction, and a mutilated gear normally out of mesh with the first-mentioned muti-- lated gear but rotatable into inesh therewith for causing its rotation. v

19. In comblnatron, a calculating machine lii cluding figure-wheels and zero-producing mechanism, and a device including figure- Wheels normally disconnected from the wheels of the calculating machine, a springactuated plate for each figure-wheel of the device, a notched arm for holding the plate in a lowered position, a link connected to the arm, a double-ended arm fulcrumed on the device and connected to the link, a projection on the zero-producing device for abutting against the arm and, "when shlftecl by the same, tending to release the springing device including figure-wheels which .stand at nines when any number shows on the figure-wheels of the calculating machine, intermediate mechanism between the figure-wheels of the machine and the device and operable by the zero-producing mechanism for rotating both sets of wheels in a subtractive direction to zero to reduce the amount showing on the calculating machine and also to reduce the amount showing on the wheels of the device an equal amount,

and means for moving one wheel of the device One unit-space in an additive direction and independently of the operation of any of the wheels of the calculating machine.

21. A calculating machine including a series of figure-wheels-and a unit-wheel, in combination with a complement-determining device also including a series of figurewheels normally standing at nines position, means for simultaneously rotating both sets of wheels in a subtractive direc-' tion until the wheels are simultaneously displaying zeros, automaticallybperated means for then disconnecting the two series of wheels for independent movement, and means for thereafter automatically causing rotation of the unit-wheel of the complement-determining device one unit-space in an additive direction to complete the compleInent-determining operation.

22. In combination, a complement-determinlng device, a calculating-machine associated therewith and lncludlng ze1'0-pr0duc ing mechanism, means for maintaining said device and machine in cooperative relation, means for releasing said maintaining-means while the calculating machine is being opferated except under the action of the zero- \,wheels "of the calculating machine, said cvcle of movements involx ing, first, the re In testimony Whereof'I afiii my signature tition of the twosets in a subtractive direcin presence of two Witnesses.

.tion and; then the rotation of one of the sets in 511 1 additive direction, to produce the EDWARD WALTER required complement-number on the figure- \Vitnesses:

" wheels of the complement-determining de- GEO. WV. DOWNING,

" vice. v ADOLPHE BOURGUIGNON. 

